Handpiece for tooth-boring machines



July )92s. 1,615,873

M. BAUER HANDPIECE FOR ToTH BORING MACHNES ,w y Filed April 18, 1927 lll Patented July 3, 1928.

UNITED. sfrar asv PATENT ori-"1era,

MARTIN BAUER, or BERLIN, GERMANY.

HANDPI'EGE FOR TOOTH-BORING MACHENES.

Application l1ed'Apri-1,18,v1927, Serial No. 184,529, and in; Germany September 24, 1926.

The hand-pieces of tooth-boring-mac'hines must, whether they are rigid with the flexible shaft or removably connected with the same, be cleaned very frequently, often several times a day and sterllized., as the work to be executed with the hand-piece requires a perfectly clean tool in. order to avoid infection. ot the cavity of the mouth. To perfectly clean the hand-piece, it has to be partly taken to pieces and' at least the sleeve of the hand-piece has to be removed to render accessible the inner elements of' the same.

Removing of the hand-piecesleeveis comparatively diiiicult and requires time, as either a tiny clamping screw has to be unscrewed7A which is diiiicult to find, or as the hand-piece-sleeve screwed onto the shifting element, has to be unscrewed'.

Owing to these inconveniences itfrequently happens that cleaning of the hand-piece, after the work isl linished is omitted and that the hand-piece is used again Without having been cleaned. l

A further inconvenience of' the handpieces Vof known type consists intheV construction o i' the shoulder-bearing7 of the rotatable axle andI in the auxiliary means for adjusting this shoulder-bearing which must be always in a quite accurateposition, as

otherwise the drill will rotate centrally butV run out of true. At. the boring a pressure will always be exerted in thehand-piece upon the shoulder of the axle and upon the stationary counter-bearing formed by the corresponding edge of the'shii'ting element, so that. the axle is rapidly wornl at this point, wherefrom results finally that the axle runs untrue in its upper conical bearing which is formed by the hand-pieces sleeve.

In order to avoid the running untrue of the drill and of the axle the sho'uldert-bear-r ing must be re-adjusted accordingly; This' is effected either by means of a vertical adjusting screw arranged on the lower side ot' the edge of the hand-piece sleeve or by means of a special screw-connection acting `upon.

the hand-piece-sleeve.

These adjusting means are also not easy to manipulate and the adjusting requires acertain skill and much time, so that the. re-adjusting of the shoulder-bearing is sometimes` omitted, this being evidently very prejudicial. In the commonly used hand-pieces the adjusting means are arranged freely accessible on the hand-piece-sleeve wherefrom results the further essential inconvenience that they are exposed to inliuences from the outer side4 and which might cause accidental displacement. It happens, for instance, frequently that at the cleaning oi the handpiece, when theysame has to be partly taken to pieces, the ladjusting screw is accidentally adjusted so that the axle is either too loose in the upper bearing or too tight, so that the handpiece 'has to be taken to pieces again for re-adjusting the shoulder-bearing. The improved hand-piece according to this invention Obviates all these inconveniences in the. simplest manner. Accordingto the invention the rear end of the hand-piece-sleeve is constructed to form a conical clamping sleeve which tightly lts on the conical shifting element without the aid of any separate auxiliary means, a bayonet-joint being proyided tor locking the two parts together. The shoulder-bear-V ing is further constructed like a bushing, adjustable in axial direction, arranged at the lower end of the shifting element, so that it is covered by the hand-piec'e-sleeve.

A hand-piece according to the invention is shown, by way of example, inthe accompanying drawing, in which I Fig. 1 shows in elevation the whole handpiece. ,y Y

Fig 2 shows in elevation the hand-piece sleeve alone and y Fig. 3 shows the hand-piece without the sleeve. v l

The hand-piece sleeve a has at its iront end a conical bearing b for the conical end c ot' the axle .Z. The shii'table element f which at its rear end has a roughened handl'e e, has the shape of a truncated cone on which tightly tits the inner wall oi' the handpiece-sleeve a which has also the shape ot' a truncatedv cone, so that these two elements are securely held together by jamming'. A bayonet-joint, consistiiro' of any angular slot g, z, in the hand-piecesieeve and of a stud z' engaging with said slot and' fixed in the shifting element serves for securely con-- necting said two elements. The inner arm 7i of the bayonet slot is slightly rearwardly inclined from below upward, so that the stud i will strongly push baci; the hand-piece sleeve and thus effect the maximum clamplng.

The bearing for the shoulder c of the axle d consists, according to the invention and as can be seen from Fig. 3, of a bushing Z mounted on the front end of the shifting element f, so that it can be adjusted in axial direction, .said bushing being threaded. 'The axle Z extends through this .bushing to the rear. The bushing Z has 4Va collar m at the front end which bears against. the edge of the shifting element f said collar being flattened at yone or several points to hold a spanner; or it has a transverse bore n designed to receive'a pin by means of which the bushing Z can be rotated. Between the collar m and the shoulder lc of the axle a thin washer o is located which forms the real bearing-surface- The threaded socket of the shifting part f which receives the threaded bushing Z is slotted 'to render its walls resilient in order to ensure a vsecure retention ofthe bushingin adjusted position. y

To take to pieces the hand-piece shown in F ig. l the bayonet-joint is disconnected by rotating the hand-piece-.sleeve to lthe right with a short jerk whereupon the same is pulled oil', which can be done instantaneously and Without any ditliculty. lVhen the shoulder-bearing has to be 're-adjusted for any reason, this can be done without any difficulty by turning the bushing Z with the aid of 'a convenient Spanner or pin. The bushing is covered by the vhand-picoe-sleeve, when the hand-piece is ready for work, so that it i'sfnot accessible from the outer side and cannot get out of adjustment accidentally. The mounting with the aid of a tightly screwed-in threaded bushing cannot be displaced accidentally .when the hand-piece is being taken to pieces. A -Y I claim Y l. A dental hand-piece comprising abody member having a conical'outer end portion,-

a spindle journaled in said body member, and having a conical outer end portion, and a sleeve enclosing the projecting portion of the spindle and conical eiid'portion of the body member and having its bore of conical form at its ends for reception of and en-v f gagement with the conical end portions of the body member and spindle, said sleevev having a fastening connection with the body.`

member operative in the fastening and un-y fastening movements to move the sleeve endi wise inward and outward on the body meniber and spindle. Y A

2. A dental-hand-piece comprising a body member having a conical outer end portion, a spindle journaled in said body member, and having a conical outer-end portion, and a sleeve enclosing the projecting portion of the lspindle and conical endportion of the body member and having its bore of conical form at its ends for reception of and engagement with the conical end portions of thev body member and spindle, said sleeve and 'a spindle journaled in said body member and having a conical outer end portion and a bearingshoulder, agthrust bearing engaging said bearing shoulder of the spindle'and'adjustably connected with the body member, and a sleeve eiiclosinggtlie projecting vportion of the body member and having its bore of conical form at its ends for receptionof and lengagen'ient with the conicalen'd portions of the body member and spindle,"said sleeve having a fastening connection with the body member operative in the fastening and unfastening movements to move the sleeve .endwise inwardv and outward on the body member and spindle.

et. A dental'hand-piece compri-sing a body member having a conicalA outer end portion kprovided with a socket-,a spindle journaled inl said body member and having a conica-l louter end portion and a bearing shoulder,

a thrust bearing member engaging said bear- 'Y ing shoulder ofthe spindle and adjiistably Vengaging the socket in the body member, j

and a sleeve enclosing the projecting portion of the spindle and conical eiid'portion ofthe bodyl member and having its'bore of` conical forni at its ends for reception of and engagement with the conical end portions of the vbody member yand v spindle, vsaid sleeve having a fastening connection with the body member operative in the fastening and un fastening movements to move the .sleeve endwise inward and outward on the bodymember andspindle. f i

5. A dental hand-piece comprising .a `body `member having a conicalv outer,Y end portion provided withA a threaded socket, a spindle journaled inv said body member and having a conical outer end portion andnarbearing; shoulder, a bearing bushing adjustably engaging'the threaded socket in the body niemfber, a bearing washer disposed between said bushin and the bearino' shoulder on the spindle, and a sleeve enclosing the projecting portion of the spindle and conical end portion of the body member and having its bore of conical form atrits ends for reception of and engagement with the conical end portionsv ofthe body member and spindle, vsaid sleeve having a fastening connection with the body member operative in the fastening and unfastening .movements vto move the sleeve endwise inward and outward on the body member and spindle.

MARTIN BAUER. Y Y

In testimony whereof I atixmy signature. 

